Postprandial lipemia in endurance-trained people during a short interruption to training

Abstract

This study examined changes in postprandial lipemia in endurance-trained people during a short interruption to training. Nine men and one woman (ages 18-55 yr) undertook fat tolerance tests after 15 h, 60 h, and 6.5 days without exercise. The test meal (1.2 g fat, 1.1 g carbohydrate, 66 kJ/kg body mass) was consumed after a 12-h fast. Postprandial lipemia increased rapidly with detraining (area under plasma triacylglycerol vs. time curve: 8.42 +/- 1.40, 11. 35 +/- 1.38, and 11.97 mM x 6 h at 15 h, 60 h and 6.5 days, respectively). In the fasted state, plasma triacylglycerol concentration (0.85 +/- 0.15, 1.09 +/- 0.12, and 1.10 +/- 0.11 mM at 15 h, 60 h and 6.5 days, respectively) and the ratio of total cholesterol to high-density-lipoprotein cholesterol increased with detraining. Values were significantly higher at 60 h and 6.5 days than values at 15 h ( P < 0.05) for each of these three variables. The serum insulin response was higher ( P < 0.05) at 6.5 days than at 15 h (81.6 +/- 11.3, 87.6 +/- 11.4, and 94.5 +/- 9.4 microIU/ml x 6 h at 15 h, 60 h, and 6.5 days, respectively). Frequent exercise is needed to maintain a low level of postprandial lipemia and insulinemia in trained people.

Effect of prior exercise on lipemia after a meal of moderate fat content

“…This is in agreement with the majority of the studies that have compared this outcome measure or an equivalent one, time-averaged concentration, after a high-fat meal consumed 12-18 h following aerobic exercise vs rest (Tsetsonis & Hardman, 1996a (moderate intensity trial), 1996b; Tsetsonis et al, 1997;Hardman et al, 1998;Gill et al, 1998Gill et al, , 2001aGill et al, , b, 2003Malkova et al, 1999Malkova et al, , 2000Gill & Hardman, 2000;Herd et al, 2001;. Three studies have found no significant difference between exercise and rest (Tsetsonis & Hardman, 1996a (low-intensity trial); Herd et al, 1998;Petitt et al, 2003).…”

“…In unison with all the relevant studies (Tsetsonis & Hardman, 1996a, b;Tsetsonis et al, 1997;Gill et al, 1998Gill et al, , 2001aHardman et al, 1998;Herd et al, 1998Herd et al, , 2001Malkova et al, 1999;Gill & Hardman, 2000;Malkova et al, 2000;Petitt et al, 2003), the postprandial glycemic response did not differ between exercise and control, confirming the strong homeostasis of plasma glucose. No difference was found in the insulinemic response either.…”

“…This is the first attempt to determine whether exercise can suppress the lipemic response to a meal approximating the macronutrient composition of the typical Western diet, that is (in terms of energy) 35-40% fat, about 47% carbohydrate, and about 16% protein (Williams, 2002). In fact, with the exception of Murphy et al (2000), who employed a diet providing 47% of energy from fat over the course of 1 day, all studies on the effect of exercise on postprandial lipemia have used test meals containing 60-93% of energy as fat, or 1.0-1.5 g/kg body mass (Maruhama et al, 1977;Schlierf et al, 1987;Klein et al, 1992;Aldred et al, 1994;Hardman & Aldred, 1995;Tsetsonis & Hardman, 1996a, b;Tsetsonis et al, 1997;Gill et al, 1998Gill et al, , 2001aGill et al, , b, 2002Hardman et al, 1998;Herd et al, 1998Herd et al, , 2000Herd et al, , 2001Zhang et al, 1998;Malkova et al, 1999;Gill & Hardman, 2000;Thomas et al, 2001;Petitt et al, 2003). Since the lipemic response to a fat meal is expected and has been shown to be positively related to the amount of fat ingested (Dubois et al, 1998), one could claim that exercise might not have a significant effect on lipemia after a meal of moderate fat content.…”

“…This can be explained by the fact that most (79%) of the difference between exercise and control in total AUC was due to the decrease in baseline TG concentration (by 25%). Most of the relevant studies have found significant decreases in incremental AUC with exercise (Aldred et al, 1994;Tsetsonis & Hardman, 1996a(moderate intensity trial), 1996bTsetsonis et al, 1997;Zhang et al, 1998;Hardman et al, 1998;Malkova et al, 1999;Gill & Hardman, 2000;Gill et al, 2001aGill et al, , b, 2003Herd et al, 2001;Thomas et al, 2001). None of the studies that found a significant decrease in total AUC has reported a nonsignificant change in incremental AUC, although a few of them have not compared incremental AUC (Gill et al, 1998;Malkova et al, 2000;.…”

Physical activity, obesity and blood lipids

“…In endurance athletes, just 60 h without training resulted in an increase of more than one third in postprandial lipaemia, with a further (but much smaller) increase after a total of six days without training. 61 This ties in well with a rapid decrease in postheparin plasma LPL activity after only two days without training, in trained men and women. 62 On this evidence, the effects of a recent training session are probably subsumed within the measures of TAG capacity reported for endurance athletes in some studies.…”